Method of manufacturing polymer electrolyte membrane fuel cell

Abstract

A method of manufacturing a polymer electrolyte membrane fuel cell includes preparing an intermediate sheet comprising a fibrous carbon material, obtaining carbon sheets by performing at least one of heat treatment or acid treatment on the intermediate sheet, and manufacturing unit cells comprising an electrolyte membrane. Electrodes are located on a first surface and a second surface of the electrolyte membrane, gas diffusion layers are located on the electrodes, and the carbon sheets are interposed between the electrodes and the gas diffusion layers. Electrochemical performance of the polymer electrolyte membrane fuel cell is improved by removing impurities, such as Fe particles and amorphous carbon, from carbon sheets through heat treatment or acid treatment.

1 . A method of manufacturing a polymer electrolyte membrane fuel cell comprising:
 preparing an intermediate sheet comprising a fibrous carbon material;   obtaining carbon sheets by performing at least one of heat treatment or acid treatment on the intermediate sheet; and   manufacturing unit cells comprising an electrolyte membrane, wherein electrodes are located on a first surface and a second surface of the electrolyte membrane, gas diffusion layers are located on the electrodes, and wherein the carbon sheets are interposed between the electrodes and the gas diffusion layers.   
     
     
         2 . The method of  claim 1 , wherein preparing the intermediate sheet is performed using direct spinning. 
     
     
         3 . The method of  claim 1 , wherein the fibrous carbon material comprises one selected from the group consisting of carbon nanofibers, carbon nanotubes, vapor grown carbon fibers, and combinations thereof. 
     
     
         4 . The method of  claim 1 , wherein a porosity of the carbon sheets is greater than or equal to a porosity of the electrodes, and the porosity of the carbon sheets is less than or equal to a porosity of the gas diffusion layers. 
     
     
         5 . The method of  claim 1 , wherein a porosity of the carbon sheets is 20% to 40%. 
     
     
         6 . The method of  claim 1 , wherein an average diameter of pores in the carbon sheets is 5 nm to 50 nm. 
     
     
         7 . The method of  claim 1 , wherein, analysis results of the carbon sheets using Raman spectroscopy include a ratio I G /I D  of a peak intensity I G  of a G band to a peak intensity I D  of a D band being 6.5 or more. 
     
     
         8 . The method of  claim 1 , wherein thermogravimetric analysis results of the carbon sheets include an amount of impurities remaining in the carbon sheets of less than 14 wt %. 
     
     
         9 . The method of  claim 1 , wherein thermogravimetric analysis results of the carbon sheets include an amount of impurities remaining in the carbon sheets of less than 3 wt %. 
     
     
         10 . The method of  claim 1 , wherein the heat treatment is performed in a temperature range of greater than 450° C. and less than 600° C. 
     
     
         11 . The method of  claim 1 , wherein the acid treatment is performed using a strong acid. 
     
     
         12 . The method of  claim 1 , wherein the heat treatment or the acid treatment are performed for 5 minutes to 30 minutes. 
     
     
         13 . A method of manufacturing a polymer electrolyte membrane fuel cell comprising:
 preparing an intermediate sheet comprising a fibrous carbon material;   obtaining carbon sheets by performing at least one of heat treatment or acid treatment of the intermediate sheet; and   manufacturing unit cells comprising an electrolyte membrane, wherein electrodes are located on a first and second surface of the electrolyte membrane, gas diffusion layers are located on the electrodes, bipolar plates are located on the gas diffusion layers, and wherein the carbon sheets are interposed between the gas diffusion layers and the bipolar plates.   
     
     
         14 . The method of  claim 13 , wherein preparing the intermediate sheet is performed using direct spinning. 
     
     
         15 . The method of  claim 13 , wherein a porosity of the carbon sheets is greater than or equal to a porosity of the gas diffusion layers, and a porosity of the carbon sheets is less than or equal to a porosity of the bipolar plates. 
     
     
         16 . The method of  claim 13 , wherein analysis results of the carbon sheets using Raman spectroscopy include a ratio I G /I D  of a peak intensity I G  of a G band to a peak intensity I D  of a D band being 6.5 or more. 
     
     
         17 . The method of  claim 13 , wherein thermogravimetric analysis results of the carbon sheets include an amount of impurities remaining in the carbon sheets of less than 14 wt %. 
     
     
         18 . The method of  claim 13 , wherein thermogravimetric analysis results of the carbon sheets include an amount of impurities remaining in the carbon sheets of less than 3 wt %. 
     
     
         19 . The method of  claim 13 , wherein the acid treatment is performed using a strong acid. 
     
     
         20 . The method of  claim 13 , further comprising performing water repellent treatment of the carbon sheets.